Modélisation numérique de la diffusion de l’humidité dans les composites

Abstract

Recently the composite materials were largely used in various sectors because of their good mechanical properties and the facility of manufacture. However these materials during the service are exposed to the influence of the environment such as, the temperature, moisture, the chemical attacks or the combination of all these effects. The composites are likely with the absorption of moisture, which this translated over the mechanical resistance and the lifespan of the composite element. The phenomenon of absorption of moisture is badly known because of the various effects of parameters. Several research was undertaken on this problem in order to predict the lifespan in service. It is difficult to quantify in the long run the water content and the nature of the degradations generated in the composite. There exist however numerical methods making it possible to simulate the absorption of moisture by using the Ficks law is first degree or second degree (permanent or non stationary mode). The report of magister, especially is directed to the discretization by the method the finite differences the absorption of moisture in a composite according to the principle of Fick in the non stationary mode. Numerical examples were treated in order to quantify the water content in the composite according to the position of the point located inside the material, according to the relative humidity and a number of layers.